首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   71505篇
  免费   4306篇
  国内免费   2348篇
耳鼻咽喉   266篇
儿科学   1501篇
妇产科学   256篇
基础医学   3510篇
口腔科学   120篇
临床医学   10330篇
内科学   18783篇
皮肤病学   255篇
神经病学   2506篇
特种医学   2679篇
外科学   5621篇
综合类   15290篇
预防医学   3265篇
眼科学   302篇
药学   8099篇
  62篇
中国医学   3902篇
肿瘤学   1412篇
  2024年   59篇
  2023年   894篇
  2022年   1784篇
  2021年   2763篇
  2020年   2633篇
  2019年   1937篇
  2018年   1929篇
  2017年   2156篇
  2016年   2335篇
  2015年   2348篇
  2014年   5506篇
  2013年   5345篇
  2012年   4609篇
  2011年   5012篇
  2010年   3957篇
  2009年   3570篇
  2008年   3543篇
  2007年   3664篇
  2006年   3373篇
  2005年   2821篇
  2004年   2300篇
  2003年   1971篇
  2002年   1556篇
  2001年   1561篇
  2000年   1300篇
  1999年   1119篇
  1998年   960篇
  1997年   916篇
  1996年   728篇
  1995年   681篇
  1994年   657篇
  1993年   502篇
  1992年   427篇
  1991年   409篇
  1990年   367篇
  1989年   299篇
  1988年   301篇
  1987年   249篇
  1986年   214篇
  1985年   269篇
  1984年   235篇
  1983年   128篇
  1982年   162篇
  1981年   143篇
  1980年   113篇
  1979年   89篇
  1978年   66篇
  1977年   60篇
  1976年   36篇
  1975年   27篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.

Background

Glutamate plays a key role for post-ischaemic recovery of myocardial metabolism. According to post hoc analyses of the two GLUTAMICS trials, patients without diabetes benefit from glutamate with less myocardial dysfunction after coronary artery bypass surgery (CABG). Copeptin reflects activation of the Arginine Vasopressin system and is a reliable marker of heart failure but available studies in cardiac surgery are limited. We investigated whether glutamate infusion is associated with reduced postoperative rises of plasma Copeptin (p-Copeptin) after CABG.

Methods

A prespecified randomised double-blind substudy of GLUTAMICS II. Patients had left ventricular ejection fraction ≤0.30 or EuroSCORE II ≥3.0 and underwent CABG ± valve procedure. Intravenous infusion of 0.125 M L-glutamic acid or saline at 1.65 mL/kg/h was commenced 10–20 min before the release of the aortic cross-clamp and then continued for another 150 min P-Copeptin was measured preoperatively and postoperatively on day one (POD1) and day three. The primary endpoint was an increase in p-Copeptin from the preoperative level to POD1. Postoperative stroke ≤24 h and mortality ≤30 days were safety outcomes.

Results

We included 181 patients of whom 48% had diabetes. The incidence of postoperative mortality ≤30 days (0% vs. 2.1%; p = .50) and stroke ≤24 h (0% vs. 3.2%; p = .25) did not differ between the glutamate group and controls. P-Copeptin increased postoperatively with the highest values recorded on POD1 without significant inter-group differences. Among patients without diabetes, p-Copeptin did not differ preoperatively but postoperative rise from preoperative level to POD1 was significantly reduced in the glutamate group (73 ± 66 vs. 115 ± 102 pmol/L; p = .02). P-Copeptin was significantly lower in the Glutamate group on POD1 (p = .02) and POD 3 (p = .02).

Conclusions

Glutamate did not reduce rises of p-Copeptin significantly after moderate to high-risk CABG. However, glutamate was associated with reduced rises of p-Copeptin among patients without diabetes. These results agree with previous observations suggesting that glutamate mitigates myocardial dysfunction after CABG in patients without diabetes. Given the exploratory nature of these findings, they need to be confirmed in future studies.  相似文献   
2.
3.
ObjectiveThere is a paucity of data concerning the use of granulocyte colony-stimulating factors (G-CSFs) in pediatric patients with acute lymphoblastic leukemia (ALL). The aim of the present study was to evaluate the effect of G-CSF use on relapse-free and overall survival in 358 consecutive, newly diagnosed pediatric ALL patients uniformly treated at the same institution between April 2012 and April 2020.Materials and MethodsPatients were evaluated in two separate periods, based on the G-CSF treatment approach. All patients who underwent ALL treatment between April 2012 and December 2016 received G-CSF (G-CSF+ arm; n: 245) in the course of the protocol for reducing the risk of febrile neutropenia and/or inducing neutrophil recovery to prevent any treatment delay. No patients after December 2016 received G-CSF, even if they belonged to the high-risk group, and these were included in the G-CSF? arm (n: 113).ResultsEstimated mean relapse-free (106.5 months; 95 % CI 102?110.8 vs 82 months 95 % CI 75.2?88.9; p: 0.794) and overall survival (111.4 months; 95 % CI 108?114.8 vs 85 months 95 % CI 80.4?89.8; p: 0.431) rates were similar between the G-CSF+ and G-CSF? groups.ConclusionsOur findings indicate that G-CSF use during ALL treatment had no effect on relapse rates or overall survival.  相似文献   
4.
目的 通过分析特发性肺纤维化急性加重期(AE-IPF)患者证候与血清生物标志物的关系,为中医辨证治疗提供参考。方法 采用观察性研究设计,收集2019年3月至2019年11月三个中心的AE-IPF患者76例,其中痰热壅肺证26例、痰浊阻肺证50例,并纳入健康志愿者10例作为对照。采用ELISA测定患者血清CCL18、HMGB1、KL-6、MMP-7、SP-A和SP-D水平,分析与中医证候的相关性。结果 AE-IPF患者血清CCL18、HMGB1、KL-6、MMP-7、SP-A和SP-D水平均显著高于健康对照组。血清CCL18、HMGB1、KL-6、MMP-7和SP-D水平在痰热壅肺证和痰浊阻肺证患者间无显著性差异(P>0.05),而血清SP-A水平存在显著性差异(P<0.05)。结论 血清SP-A与AE-IPF证候存在一定的相关性,血清SP-A的浓度升高,与痰热壅肺证关系越密切,反之,血清SP-A浓度降低,则与痰浊阻肺证关系越密切。AE-IPF痰热壅肺证患者的预后可能较痰浊阻肺证患者更差。  相似文献   
5.
6.
7.
Transient stress hyperglycemia in the setting of acute myocardial infarction is a frequent phenomenon. Its transient nature should not dissuade the clinician from management of elevated blood glucose in a patient after an ST-elevation myocardial infarction. This case presents an adult patient after an ST-elevation myocardial infarction with transient stress hyperglycemia and the evidence used to identify optimal pharmacologic management and secondary prevention.  相似文献   
8.
【摘要】目的 探讨二维斑点追踪显像技术(2D-STI)评估新生儿窒息合并心肌损害后左心室整体及局部心肌的纵向收缩功能在早期诊断窒息新生儿心肌损害中的临床价值。方法 选择2019年07月至2020年12月期间在右江民族医学院附属医院新生儿科住院的足月窒息新生儿61例,经临床确诊合并心肌损害,根据Apgar评分分为轻度组31例和重度组30例,选择同期住院出生的正常足月新生儿30例作为对照组。检测受检者的血清肌酸激酶同工酶(CK-MB)、肌钙蛋白(cTnT)、左室舒张期前后径(LVDId)、左室射血分数(LVEF)、左室短轴缩短率(LVFS)、辛普森法左室射血分数(Simpson EF)、左室三腔心整体应变(GLS-LAX)、左室四腔心整体应变(GLS-A4C)、左室两腔心整体应变(GLS-A2C)、左室整体应变(GLS-AVG),分析GLS-AVG和CK-MB、cTnT三者的相关性。结果 三组间CK-MB和cTnT比较差异有统计学意义(P<0.05)。三组间性别、体重、胎龄均无统计学差异(P>0.05)。三组间LVDId、LVEF、LVFS、Simpson EF比较差异无统计学意义(P>0.05)。GLS-AVG与CK-MB呈负性相关(r=-0.515,P=0.000),GLS-AVG与cTnT呈负性相关(r=-0.912,P=0.000)。结论 GLS-AVG与CK-MB、cTnT具有相关性,GLS-AVG可作为窒息新生儿心肌损害早期诊断指标。  相似文献   
9.
10.
《Clinical microbiology and infection》2022,28(8):1152.e1-1152.e6
ObjectivesDespite the possibility of concurrent infection with COVID-19 and malaria, little is known about the clinical course of coinfected patients. We analysed the clinical outcomes of patients with concurrent COVID-19 and malaria infection.MethodsWe conducted a retrospective cohort study that assessed prospectively collected data of all patients who were admitted between May and December 2020 to the Universal COVID-19 treatment center (UCTC), Khartoum, Sudan. UCTC compiled demographic, clinical, laboratory (including testing for malaria), and outcome data in all patients with confirmed COVID-19 hospitalized at that clinic. The primary outcome was all-cause mortality during the hospital stay. We built proportional hazard Cox models with malaria status as the main exposure and stepwise adjustment for age, sex, cardiovascular comorbidities, diabetes, and hypertension.ResultsWe included 591 patients with confirmed COVID-19 diagnosis who were also tested for malaria. Mean (SD) age was 58 (16.2) years, 446/591 (75.5%) were males. Malaria was diagnosed in 270/591 (45.7%) patients. Most malaria patients were infected by Plasmodium falciparum (140/270; 51.9%), while 121/270 (44.8%) were coinfected with Plasmodium falciparum and Plasmodium vivax. Median follow-up was 29 days. Crude mortality rates were 10.71 and 5.87 per 1000 person-days for patients with and without concurrent malaria, respectively. In the fully adjusted Cox model, patients with concurrent malaria and COVID-19 had a greater mortality risk (hazard ratio 1.43, 95% confidence interval 1.21-1.69).DiscussionCoinfection with COVID-19 and malaria is associated with increased all-cause in-hospital mortality compared to monoinfection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号